                                        :min      0
                                        :max      (dec rows)
                                        :style    #js {:width "30px"}
-                                       :onInput  (partial modify :start-row)}))
+                                       :onInput  (partial modify-int :start-row)}))
             (dom/label nil
                        "Start Column: "
                        (dom/input #js {:type     "number"

                                     :min      2
                                     :max      99
                                     :style    #js {:width "30px"}
                                     :onInput  (partial modify :columns)})))
        (dom/div
          nil
          (dom/label nil

                                       :min      0
                                       :max      (dec rows)
                                       :style    #js {:width "30px"}
                                       :onInput  (partial modify-int :end-row)}))
            (dom/label nil
                       "End Column: "
                       (dom/input #js {:type     "number"
